good find laser, thats an interesting site.
3. Some tactical squads download their back-up magazines by one round to make a tactical reload (which is done with a round chambered and the bolt forward) easier. This is because of the reduced upward pressure on the rounds
thats the only reason i dont fully load some mags for the ar. with a fully loaded stirling manufactured 20 round mag its an arm wrestle to get it locked in the rifle with the bolt carrier foward. stirling mags are top quality with tough springs that dont easily fatigue, but ive found its not such a problem with the seemingly weaker springed colt and gi mags. if you leave any mag fully loaded or even a few rounds shy of fully loaded for an extended period of time it stands to reason it must cause some fatigue to the spring, with the degree of fatigue and any resulting reliability issues with the mag ( if any) mostly determind by the quality of the spring. I bought a bunch of precision mag industries steel 40 round mags for the ar and armalite from numrich and killed one by leaving it fully loaded for 2 or 3 months. it stuffed the spring in a $24.95 mag... which i didn't think was exactly cheap and expected better